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a. n; WILLIS. SEMI-AUTOMATICTELEPHONE SYSTEM. TION FILED )ULV LING-NENEWED APR. 23, 1919- MfPLlGA R n AR. W E? QM 7 mm rm? Mm W 4 mm 4%? nP o 93 w Q95 a s WM .Vb M w B. DQWILLIS. SEMLAUTOMATIC TELEPHONE'SYSIEM.APPLIQA'HON FILED l-ULY 7. I9l3- RENEWED APR. 28, H9.

Patent/ed June 11?, 1939.

2 Mznwsam 2.

nnnnn n. WILLIS, or CHICAGO," nitmois, nssieuon; To AUTOMATIC ELECTRICCOMPANY, or CHICAGO, ILLINOIS, ecoiaronnrion or. ILLINOIS. 1

SEMI-AUTOMATIC TELEPHONE naoegeee.

. specification of Letters Patent. v Pattem thgd June 1W3, 19119..

Application filed an 7, 1913, Serial in, 777,659. Renewed April as,1919. Serial rm. 2,343.

To all whom it may concern: f

Be known that I, BERNARD D. .Wnms, a citizen of the United States ofAmerica, and resident of Chicago Cook County, Illinois, have inventedcertain new and useful Improvements in Semi-Automatic Telephone Systems,of which the following is a specification.

My invention relates to improvements in semi-automatic telephone systemsin which automatic district exchanges are employed with a manual mainexchange. In such systems, certain of the subscribers lines, insteadated to connect with the called line. It will" thus be seen that in sucha connection two trunks between the district and main ofiices wereemployed;

It is the object of my present invention to provide means whereby thetalkin tion between two subscribers of a single district office isconfined entirely to apparatus- -located at this district oflice,thetrunk line extending to the main exchange or manual switchboard onlybeing employed for talking purposes when thecalling subscriber desiresto establish a connection with a subscriber whose line terminates insome other exchange.

By my' present invention a calling subscriber, upon initiating a call byremoving his receiver from the hook, operates. his individual lineswitch to select'an idle trunk.

which has a branch extending to the manual switchboard. Upon the seizureof this trunk a signal is displayed upon the switchboard to indicate tothe operator that a connection is desired. The operator then plugs inand,

conne'c- Ceiver 180, transmitter 181, hook switch .182

condenser 183 and the ringer 184.

back over the same trunk to operate automatic switches in the districtofliceand thus establish connection with the called line.

My invention will be more clearly understood by reference to the accomanying drawings, in which I have illustrate my in v connection withautomatic (Fig. 1) and a called substation A (Fig. 2) a in a systemembodying the principles oi my invention.

In Fig. 1 there is shown a', subscribers substation A the lineconductors ofwhich terminate in the individual or line switch D. Theline switch shown at D is one of ajgroup or similar line switches theplunger (not shown) of which engage a shaft and are controlled bythe.operation of the master switch shown at E in such a manner that theyare, when in normal position, held directly in frontof the terminals ofa trunk line leading through a group of relays F to a selector switch H.At C there is shown a manual operators cord circuit to which is added acalling device L. At ll (Fig. 2) a connector switch is shown which isone of a group of connectors to which the selector H has access. At 1) aline switch is shown which is similar. in all respects to the one shownat D. The substation A is in all respects similar to the substationshown -at A. The apparatusshown in both figures, with the exception ofthe cord circuit C, is located in a district or sub-exchange, while thecord circuit C is located in the main exchange.

Thesubstation A is of the usual common battery manual type, consistingof the reline and master switches disclosed in Brit- 1% ish Patent No.26,30L of 1906, issued to c; R. W. James, being, however, of theparticular type shown in British patent to '1. G.

-Martin No. M19 of 1910. As herein represented, the line switch Dcomprises among; ion

other details a plunger (not shown) attached to the end of a so-calledplunger arm 10 which is controlled by a magnet 11. The

magnet also controls the armatures 12 and13 and is composed of t urwindings, namely, a 11a pull-down winding 14, holding or cut-ofi'winding '15, a'line winding 16 and an auxiliary winding 17. The magnet11 is suitably mounted on a bracket '18 on which are pivoted thearmatures 10, 12 and 13. The magnetic circuit of the two windings l4 and15 is kept separate from that of the windings 16 and 17, so that thearmatures at one end of the magnet are not affected by the ener- .bankof contact springs, forcing the springs 2, 4, 6 and 8 into contact withthe springs 3, 5, 7 and 9, respectively. Although only one set ofsprings (29) is shown, each line switch D is provided with a number ofsuch groups, each groupforming the terminal of a. trunkline leading to agroup of relays F,

which relays" are in turn connected directly to a first selector H. Therelays 21 and 2-2 are bridged across the trunk line leading to therelays F in series with battery and become energized upon the operationof the line switch plunger upon the calling sub-- scriber removing thereceiver from the switch hook. These relays are themeans of supplyingbattery current to thecalling sub.- scriber. The relav 23 is aslow-acting relay the springs of which, and the springs of theline-switching relay 24, control the circuit of the line signaling relay25. The circuit is traced through the relay 26, the function of' wh1chis to repeat the impulses created by the calling device springs L. Acondenser 27 is inserted in one line conductor (Fig. 1). The completeoperation of the group of relays F will be explainedlater.

Theselector H consists of the usual verti cal and rotarv magnets 19 and20 for the purpose of raising'and rotating the shaft wipers 35, 36 and37 onto an idle trunk lin'e leading to the connector l, the line relay26, the release relay 29 (which is slow acting), private magnet 30,private relay 31, line switching relay24 and a rotary interrupter relay32. The selector H is also provided with the usual side switchconsisting oftwo side switch wipers 33 and 84. t

'The connector I is somewhat similar to that disclosed in United StatesLetters Pat out No. 815.176, granted March 13, 1906, to Keith, Ericksonand Erickson, the circuits, however, being modified to adapt the switchfor use in this particular semi-automaticsys tem. Like the selector, theconnector is provided with a shaft (not shown) carrying the wipers 38,39 and 40, which shaft is controlled by the vertical and rotary magnets41 and 42 through the medium of th line moaeae relays 51- and 52. Theside switch, consisting of the side switch wipers 43, 44, 45 and 46, iscontrolled by the private magnet 47 in the usual manner. The connectoris provided with a so-called back-bridge relay 48 through which thecalled subscriber is supplied with talking current. This relay is alsothe means of energizing the ringing cutoff relay and closing the circuitof the relay 76 in the cord circuit C (Fig. 1) when the calledsubscriber takes his receiver ofi the switch hookto answer the call.Ringing current is sup-plied to the called line by means of the ringingrelay 51. current is sentback over the line to the calling subscriber bythe energization of the busy relay 53. 54 and 55 represent the usualrelease magnet and relay, the former operating to release the connectorswitch in the well-known manner.

The line switch D is exactly the same as the line switch D and althoughthe master switch for controlling the group. of line switches to whichthe switch D belongs is not shown, it can be of the same type. as themaster switch E.

' Having given a general description of the apparatus lnvolved in myinvention, 1 will now explain how a subscriber at the substation Aobtains connection with a subsoriber at the substation A. We will assumethat the number of the subscriber at the substation A is 220.. Upon thesubscniber at the substation A taking his receiver off theswitch hook, acircuit is closed through the line winding 16' of the individual switchD from ground G through contact of the springs 57 and 58, conductor 59,through the telephone and back over the conductor 60, through contact ofthe springs 61 and 62 and through thewinding 16 to battery B. Upon theline winding becoming energized, the armature 12 operates to close thesprings 63 and 67, thereby closing a circuit from ground G through thepulldown coil 14 and through the auxiliary winding 17 and the contact200 to battery B and to ground G. The winding 14 energizes and attractsthe plunger arm 10, together with ,the armature 13, which latterbreaksthe contact of the springs 61 and 62, 57 and 58, thus opening thecircuit of the line winding 16, the armature of which, how.- ever, doesnot fall back at this time, because the auxiliary winding 17 is stillenergized in series with the winding 14. Upon the plunger farm 10 beingcompletely drawn down, the plunger of, the line switch is thrust intothe bank terminals, pressing the springs 2, 4, 6 and 8 'into contactWiththe springs 3, 5, 7 and 9, respectively. By the same operation thesprings 64 and 65 make contact to short-circuit the auxiliary winding17, which allows its armature to fall ba k, opening the cir uit of thepull-down A busy tone this time they are stillopen.

winding 14. This does not take place, how-. ever, until after thehold-down coil 15 has been energized by a circuit over the release trunk66 from ground G Upon the sprmgs 2, and 4 making contact with thesprings 3 and 5, the line connection is extended to the two line relays21 and 22'- of'the group of relays F, which thereupon energize. Therelay 21, upon energizing, operates its springs to complete the circuitof the holding coil 15' from ground G through the contact ofthe springs67, springs 7 and 6 and through the winding 15 to the battery lead 100.The relay 22, upon energizin closes a circuit through the slow acting reay 23 traced from ground G springs 152, and relay 23 to the battery B.Upon the energization of the relay 23, a 'cir-. cuit is closed from thebattery lead 100 through the springs 68, springs 69 and'70,

relay 26, conductor 91, contact of the answering jack J and through thepilot relay 25-to' ground G Upon the relay 26 energizing, the circuit ofthe relay 28 is closed from ground G, contact of springs 78' and throughthe relay 28 to the battery lead 100. The relay 28, uponenergizing,operates its armature to close the circuit ofthe slow-acting relay 29,which in turn operates its springs to prepare a circuit for the verticaland rotary magnets 20 and 19, the former through the contact 151-and thelatter from ground G through the contacts 153 and 154 and through theinterrupter relay 32 'to the rotary magnet These c1rcuits will bementioned again later, as at relay 25 energizing, the circuit of thepilot lamp 74 is closed, thus displaying the'same to indicate to'theoperator that a subscriber desires to make a call. 'The energization ofthe slow-acting relay'23 also connects an:

additional ground connection to the holding trunk 66 and the lineswitching relay 24 from ground G through the contact 150. No circuit isclosed through the relay 24 at this time, owing to the side switch wiper33 being in the first position at this time. The relay 23 prevents therelease of the connection as 'far as it has gone should the callingsubscriber operate his receiver hook up and down while the operator atthe main oiiice is making the call, for this relay being slowacting doesnot deenergize as quickly as theline relay 21, and thus maintains thecircuit of the holding winding closed.

Upon the signal 74 being displayed, the

operator inserts the plug Pinto the jack J in the usual manner, operatesthe listening key K and asks the calling subscriber the number of. thedesired line. Upon the plug.

P being inserted into the jack .l, the circuits of the relays 76 and 191are simultaneously closed and the lamp 74 is extinguished by.

the deinergization of the relay 25. if the Upon the' desired number,which we have assumed to be 220, is in the same semi-automaticsubexchange as the calling; subscriber, the oper- 'ator operates, thecalling device key K,

which cuts the relay 76 out of the circuit and cuts the calling devicesprings L into the circuit, and then proceeds to call in the usualmanner. As soon as the key K is operated to include the calling device Lin the circuit,

the relay 76 deenergizes, allowing its armature to drop back and againclosing the circuit of. the lamp 174 at the contact 175. The operatorthen operates the calling device to open and close the springs L twiceto thus send the impulses for the first digit 2 over the line to operatethe first selector H. The

.circuit of the relay 26 is thus bro-ken twice,

which in turn twice breaks the circuit of the relay 28 at the contact78. The armature of the relay 28 falls back a corresponding -number oftimes. The relay 29 being -slow-- acting does not deenergize during themo mentary deenergization of the relay 2'8 and a circuit is closed twiceextending from ground 6- through the private relay. 31 in series withthe vertical magnet 20 and through the side switch wiper 33 to batteryand thence to ground. The vertical magnet 20 operates to raise the shaftwipers 35,36

and 37 two steps, opposite the rowof contacts in which terminate thetrunk lines leading to the connector 1. After the last of the verticalimpulses has been delivered, the

slow-acting relay 31, in series with the vertical magnet, deenergizes,thereby breaking the circuit of the private magnet 30. The armature ofthe magnet falls back to release the side switch from first to secondposition,

to open the circuit of the relay 26 to thus balance the line and to cutthe negative and positive lines through to the connector I, energizingthe two line relays 51 and 52. The circuit for the latter relay extendsfrom ground G through said coil, conductor 80,- line wiper 36, springs81, conductor 90, through the jack and plug of the cord circuit- C andthrough the relay 191 to the b'attery B The circuit of the formerextends from, ground G (Fig. 1) through the relay 75, calling device srings L and the key K, through the plug and the jack J of the cordcircuit, conductor 91,-springs 82, conductor 83. side switch wiper 43,springs 85 and through the line relay 51 to the batteryB. Upon the sideswitch wiper 34(Fig.

1) passing tolthirdeposition, ground ten-.

' 'tial from ground .G is placed on al the ftained closed the entirelength of time the plug P is inserted into the jack J (Fig. 1).Therefore, saidjrelay is energized, retaining itsarmatiire and springsinoperated position. Upon the-relay'51 energizing, a circuit is closedfrom ground G through the contact springs 93 and 92, 'contactsprings 94.of the relay 52 and through thesloW- acting releaserelay 55 to" thebattery B.

When the relay 55 is once energized, it

7 forms a locking circuit for itself from ground G through the-contact106 of its own springs 'and...through; jthe contact of' springs 94,thence through ,its' own winding to the battery 13. Upon the springs ofthe calling device again being opened twice momentarily, the line relay;51%.is denergized;

a corresponding number. of timesto operate the vertical magnetin theusual manner to raise the shaft wipers 38, 39 and 40 two steps. Theslow-acting;private' relay 95 is 47 allowing the side switch to passmachine 102 to .mittently energizing the relay 51 to dlsconin serieswith the verticalmagnet /41- and upon the last impulse of this seriesbeing delivered, this relaydeenergizes, thereby breaking the circuit ofthe private ma rom first 'to second position and transferringbatterycurrent from the vertical'magnet to the rotary magnet. Thecallingdevice is now operated for the third dig 1t 0,, transmitting ten-impulses over the line'and operating the rotary magnet 42 to rotate theshaft wipers 38, 39 and 40 around ten steps. After the last impulse'ofthe series has'been delivered, the private magnet again dener .gizes andthe side switch passes to third position. At this time the shaft wipersare resting on the desired contact, and upon the side switch wiper, '46passing to third posit1on, the circuit through the bridge-cut-ofi relay98 of the line switchcl) is closed, which energizes and presses togetherthe springs 99, thus completing the connection 'to the substation A.'Upon the side switch wiper 44 passing to third position, a circuit isclosed from battery B through said side switch wiper, contact of thesprings 101, and through therelay 51 to the interrupter ground G therebyinternect the calling line from the called line at the springs. of saidrelay, and to place the ringing generator Macross the called line.

hook tb answerthe call; the back-bridge relay is energized in the usualmanner to close 1 switch wiperj45,-through the 11%P6pWlIldil'lg .thesame'more fully in this specification.

neoaeee The ringing generator M sends ringing current; over-the calledsubscribers line to ring the bell at the substation. -When the operatorhas finished cal1ing, she restores the key K- to its-normal position,thereby cut- 70.

ting out of the circuit the resistance coil 7 5 and cutting in the cordcircuit relay 76. Since'tlie slde switch ,wiper 43 (Fig; 2') is inthirdosition, the circuit including the relay 76 1s open at the springs 155of the back-bridge relay 48. Therefore, the con-- tact spring 175-remains closed and the line lamp 174 remains lighted. Upon the calledsubscriber taking his receiver off the switch the circuit of the ringingcut-ofi relay 50. The circuit of the relay 48 extends from ground Gthrough thecontact 106, through.

the lowerfwinding of the relay 48, contacts [107 and 108, through thecalled subscribers 5 telephone, contact 99, :contacts 110 and 111 of therelays 51 and 47, respectively,'-side of the relay 48 and through atteryB'to groundfG. The circuit of the relay 50 exitendsufrom ground G overpart of the circuit alreadytraced, through the contact and relay 50 andthe side switch wiper 44 to the battery B. When once thisrelay isenergized it remains locked by the springs 114 making contact. Thislockin'g'circuit is to preventthe called subscribers" bell from ringingagain should he hang up his receiver before the calling subscriber hasre placedhis receiver. Theenergization of the back bridge relay alsooperates its springs [to close the circuit through'the line relay 76 inthe cord circuit of the main office (Fig. 1), said circuit extendingfrom ground G 106 throu h said relay, f'key Kf, plug P and thejackcontact 82 ofthe relay 24, conductor 83, side switch wiper 43,contact 155 and through the elay 51"to battery'B. Therefore, it .is seenthat as soon as the called subscriber answers the call, the operator isnotified of this fact by the lamp 174 being extinguished.

Should he called subscriberslrne be busy,

there will be a guarding ground potential 115 on the contact on whichthe private wiper- 40 comes to rest, retaining the private magnet in anoperated position to keep the lines open at the contacts 107 and 111.The busy relay 53 is energized and the usual busy tone I from the busymachines is thrown back over the callin subscribers line. The busycircuit just re erred to iswell known in the art and it is thoughtunnecessary to describe To release the connection after the conversationhas been completed, the called subscriber gives the operator at the mainofli'ce the disconnect signal in the following man- "per; Upon returninghis receiver to the we conductor 83,.side switch wiper 43, springs anewswitch hook, thcircuit ofthe back-bridge relay 48 is broken at thesprings 170. This 7 6 of the cord circuit C (Fig. 1) is deenergized bythe breaking of the contact springs" 155. This circuit extends fromground G through. the line relay 76,-key K, plug P..-

and the jack J, conductor 91, springs 82,

155 and through the line relay 51 of the connector to'battery'B. Uponthe relay 7 6 nal is received by the operator, whereupon in the cordcircuit (3 deenergizing, the lamp 174 is lighted and the usualdisconnect sigtaken from the line switching relay 24, v

which deenergizes to disconnect the line conductors at the springs 82and 81. At the same time a circuit is closedat the springs 159 oftherelay 24, through the release magnet 160 and off-normal springs 161to the battery lead 100. Upon .the' release magnet 1G0 energizing, theswitch shaft 11s returned to its normal position, and as soon as itreaches its normal position it'opens the contact of the ofi'normalsprings 161, thereby allowin the release magnet to deenergize.

Also w en the springs 150 of the relay 23 break contact, the circuit ofthe holding coil 15 of the line switch D isbroken,,wh1ch deenergizes andallows the plunger arm .10 to return to its normal position, togetherwith. the plunger, thereby breaking the line extension at the banksprings 29. Upon the selector H thus being released, the llne relays 51and 52 of the connector switch I are deenergized, the springs of thelatter breaking their contact to openthe circuit of the release relay55. This relay, as in the selector II, deenergizes to close the circuitof the release magnet 54,. releasing the switch in the well-known mannerand-leavin the line in readiness for further use.

n the foregoing it has been explained how the operator calls back overthe same trunk line over which the signal is received in order to callthe subscriber called for when his line terminates in the samesub-exchange as that of the calling subscriber. If. the subscribercalled for had been a subscriber of the main exchange, the connectionwould have been completed by the insertion of the calling plug P of thecord G into a multiple jack of the line in. the usual manner.

In a system of the character described herein there would be-suitabletrunk lines,

in addition to those shown, leading from the ing the operator and fortransmitting the departing main exchange to automatic switches in thesub-exchange for the purpose of establishing connection between callingsubscribers of'the main exchange andcalled subscribers'of thesub-exchange. As trunks for this pur ose are known and do not form afeature 0 the present invention, itis not thought necessary'toillustrate the same herein. I It will thusbe seen that I have devised avery eflicient form of semi-automatic district 5 i system in which eachtrunk to which the subscribers individual switches have access has abranch leading to the operators switchboard, as" well as a branchleading to an individual selector switch in the district exchange. Itwill furthermore be seen that the trunk lines which are employed for ex'tending the talking connection are the same trunk lines which areemployed for signalimpulses back from the operators board for thepurpose of operating the automatic switches'to connect with a calledsubscriber; While I have ill'iis'trated and described my invention inconnection with a semi-automatic system of a particular type, it wilhfofcourse, be understood that I do not wish to r limit myself to thearticular system shown and described, but t at many other forms ofautomatic switches and operators cord circuits can be employed without.in any way from the spirit and intentof my invention.

'VVhat I- claim as my invention is '1. In a telephonesy'stem, a" trunkline, having two branches having a common terminal, means for extendinga talking connection from said terminal over either of said "branches,an automatic switch associated 'ing two branches having a commonterminal,

means for extending a talking connection from said terminal over eitheri of said branches, an automatic switch associated with one of saidbranches, said switch having contact arms-normally disconnected fromsaid trunk, a relay normally connected with 1 said trunk, means fortransmitting impulses back overthe'other branch to operate said relay,means controlled by said relay for controlling the operation of saidswitch, and means controlled by the operation of said switch forconnecting said switch arms with said trunk and for breaking the circuitof said relay.

3. In a telephone system, a manual switchboard, an automatic switch, atrunk line havp terminal, and lines divided into groups ex- -tendingfrom said automatic switch, sad

ing two branches having a common terminal, one of said branches leadingdirectl to a jack in said switchboard and the 0t er said automaticswitch, means for selzing said common terminal, a condenser in saidtrunk, a relay bridged across said trunk on one side of said condenser,a signal at said switchboard controlled-by said relay, and'means fortransmitting impulses back over said trunk from said manual switchboardto opcrate said automatic switch.

4. In a telephone system, a manual switchboard, "an automatic switch, atrunk line hav- 111g twobranches havlng a common terminal,

'one of said branches. leading directly to a jacklin said switchboardand the other to said automatic switch, means for seizing said commonterminal, a condenser in said trunk, a relay bridged across said trunkon one side of said condenser, a signal at said switchboard controlledby said relay, a second relay connected with said trunk on the otherside of said condenser, means at said manual switchboard forintermittently energizing said second relay, and means controlled by theoperation of said second relay extending a talklng connection over.either of said branches, a signal associated with said jack adapted tobe displayed upon seizure of said trunk, means for rendering said sig"nal moperative when the cord circuit is con-' nected with said jack,means in said cord cir cuit for transmitting impulses back over saidtrunk to operate said automatic switch while said connection is extendedto said common switch having motion in one plane to select roups andmotion in a plane at right angles iereto to find a line in a selectedgroup.

6. In a telephone system, a plurality of subscribers lines, a trunkline, a manual switchboard, means for extending a connection from one ofsaid subscribers lines over another of said subscribers lines, means atsaid trunk to said manual board, means for extending said connectionfrom said board to a second of said subscribers lines, automaticswitches for extending a connection to said manual board fortransmitting impulses back over said trunk to operate said switches, andlines divided into groups extending from said automatic switches, saidswitches having motion in one plane to select groups and motion in aplane at right isoaeae angles thereto to find a line in a selectedgroup.

7. In a telephone system, a trunk line having two branches having acommon terminal, means for extending a talking connection from saidterminal over either of said branches, an automatic switch associatedwith one of said branches, a relay connected with said trunk, means fortransmitting impulses back over the, other branch of said trunk tooperate said relay, means controlled by the operation of said relay foroperating said automatic switch, means controlled by the operation ofsaid switch for breaking the circuit of said relay, and lines dividedinto groups extending from said automatic switch, said switch havingmotion in one plane to select groupsand motion in a plane at-rightangles thereto to find a line in a selected group.

8. In a telephone system, a trunk line having two branches having acommon terminal, means for extending a talking connection from saidterminal over either of said branches, an automaticv switch associatedwith one of said branches, said switch having contact arms normallydisconnected from said trunk, a relay normally connected with saidtrunk, means for transmitting imi pulses back over the other branch tooperate said relay, means controlled by said relay' for controlling theoperation of said switch, means controlled by the operation of saidswitch for connecting said switch arms with said trunk and for breakingthe circuit of said relay, and lines divided into groups extending fromsaid automatic switch, said switch having motion inone plane to selectgroups and motion in a plane at right angles thereto to find a line in aselected group.

9. -In a telephone system, a trunk line having two branches having acommon terminal,

means for extending 'a talking connection 7 from said terminal overeither of said branches, automatic switches associated with one of said.branches, a condenser in said trunk, arelay connected with said trunk onone side of said condenser, means for transmitting impulses back overthe second branch of said trunk to operate said relay, means controlledby the operation of said relay for controlling the operation of saidautomaticswitches, and lines divided into groups ex I tending from saidautomatic switches, said switches having motion in one plane to selectgroups and motion in a plane at right angles thereto to find a line in aselected group.

10 'In a telephone system, a manual switchboard, an automatic switch, atrunk line having two branches having a common terminal, one of saidbranches leadingdirectly to a jack in said switchboard and the other tosaid automatic switch, means for seizing said common terminal forextending a connection over either of said branches, a

assesses condenser in one side of said trunk, a relay connected withsaid trunk on one side of said relay to control the operation of saidautomatic switch, whereby a talking circuit is set up over the saidcommon terminalthrough the medium of said manual switchboard, and linesdivided into groups extending from said automatic switch,said switchhaving motion in one plane to select groups and motion in a plane atright angles thereto to find a line ina selected group.

11. In a telephone system, a manual switchboard, an automatic switch, atrunk line having two branches having a common terminal, one of saidbranches leading di rectly to a jack in said switchboard and the otherto said automatic switch, means for seizing said common terminal, acondenser in said trunk, a relay brid e across said trunk on one side ofsaid. condenser, a signal at said switchboard controlled by said relay,

means for transmitting impulses back over said trunk from said manualswitchboard to operate said automatic switch, and lines divided intogroups extending from'said automatic switch, said switch having motionin one planeto select groups and motion in a plane at right anglesthereto to find a line in a selected group.

v12. In a telephone system, amanual switchboard, an automatm switch, atrunk line having two branches having a common terminal, one of saidbranches leading directly to a jack in said switchboard and the other tosaid automatic switch, means for seizing said common terminal, acondenser in said trunk, a'relay bridged across said trunk on one sideof said condenser, a signal at said switchboard controlled by saidrelay, a second relay connected with said trunk on the other side ofsaid condenser, means at said manual switchboard for intermittentlyenergizing said second relay, means controlled by the operation of "saidsecond relay for controlling the operation or said automatic switch, andlines divided into groups extending from said automatic switch, saidswitch having motion in one plane to select groups and motion in a planeat right angles thereto to find a line in a selected group.

13. In a telephone system, a subscribers line, a plurality of trunklines, a trunk-selecting switch adapted to make connection with an idleone of said trunks, each of said trunks having two branches, asprmg jackat the end of one of said branches, an automatic switch in which theother branch terminates,

a cord circuit associated with said spring jack having means fortransmitting impulses back over one branch to operate the automaticswitch associated with the other and motion in a plane at right anglesthereto to find a line in a selected group.

14. In a telephone system, a subsciibers line, a plurality of trunklines, a trunk-so lecting switch adapted to make connection with an idleone of said trunks, each of said trunks havingtwo branches, a springjack at the end of one of said branches, an automatic switch in whichthe other branch terminates, a signal associated with each jack, meansfor displaying the corresponding sig nal when said trunk-selectingswitch makes connection with one of said trunks, means associated withsaid selected. jack for trans mitting impulses back over one branch ofthe selected trunk to operate the automatic switch associated with theother branch of said trunk to extend 'a connection over said l commonterminal, and lines divided into grou s extending from said automaticswitc said switch having motion in one plane to select groups and motionin a plane at right angles thereto to find a line, in a selected group.

15. In atelephone system, a subscribers line, a plurality of trunklines, a trunk-selecting switch adapted to make connection with an idleone of said trunks, each of said trunks having two branches, a springjack at the end of one of said branches, an automatic switch in whichthe other branch terminates, a signal associated with each jack, meansfor displaying the corresponding signal when said trunk-selecting switchjmakes connection with one of said trunks, a cord circuit with a plugadapted to be connected with said selected jack, means controlled by theinsertion of said plug in said jack for rendering said signalinoperative, an impulse transmitter associated with said cord circuitfor transmitting impulses back over one branch of said'sele'cted trunkto operate the automatic switch associated with the other branch of saidtrunk, and lines di- 'ided into groups extending from said automaticswitch, said switch leaving-v motion in one plane to select groups andmotion in 'a plane at right angles thereto to find a line in a selectedroup.

branch 'operated when a cgnnection is extendedthereover.

17 L In a telephone system, a local exchange and a distant exchange, atrunk line having controlled by the 0 eration of said switch twobranches, having a common terminal, means for extending a talkingconnection from said terminal over one of said branches to thesubscribers of the local exchange and over the other branchto thesubscribers of the distant exchange, automatic progressively movableswitches associated with one of said.

'branches,'means for transmitting impulses back over the, other branchto operate said automatic switches, and a signa'l associated with saidother branch operated when a connection is extended thereover. I

18. In a telephone system, a trunk line having two branches having acommon terminal, means for extending a talking connection fromsaid'terminal over either of said branches, anautomatic switchassociated with one of said branches, a relay connected with-said trunk,means for transmittin impulses back. overthe other branch of said trunkto operate said relay, means controlled by the operation of said relayfor operating said automatic switch, means for breaking the clrcuit ofsaid relay, a signal associated with one of the branches,

and means under the control of the automatic switch in the other branchfor rendering said signal inoperative over the trunk. 19. In a telephonesystem, a trunk line having two branches having a common terminal, meansfor extending a talking connection from said terminal over either ofsaid branches, an automatic switch associated with one of said branches,said switch having contact arms normally disconnected from said-trunk, arelay normally connected with said trunk, means for transmitting impulses back over the other branch to operate said relay,- meanscontrolled by said relay for controlling the operation of said switch,means controlled by the operation .of said switch for connectin saidswitch arms with said trunk and for breaking the circuit of said relay,a signal associated with one of the branches, and means under thecontrol of the automatic switch, in the other branch for rendering saidsignal inoperative over the trunk.

20. In a telephone system, an automatic switch, a trunk line having twobranches having a common terminal, one of said branches leading -.tosaid automatic switch and the other of said branches terminating inaspring jack, an operators cord circuit adapted to be, connected withsaid jack, means for seizing said common terminal for extending atalking connection over either of said branches, a signal associatedwith the branch terminating in said jack adapted to be displayed uponseizure of .said trunk,

isoaeae means forrendering said signal inoperative when the cord circuitis connected with said jack, means in said cord circuit fortransmitting' impulses back over said trunk to ,operate said automaticswitch, lines divided into groups extendin from said automatic switcsaid switch aving motion in one plane to select groups and motion in aplane at right angles thereto to find a line in a s elected group, andmeans under the control of said automatic switch in the other branch forrendering said signal inoperative over the trunk.

21. In a telephone system, a trunk line having two branches havingv acommon terminal, means for extending a talking connection from saidterminal over either of said branches, 'an automatic switch associatedwith one of said branches a relay connected with said trunk, means 'ortransmittin impulses back over the other branch of sai trunk to operatesaid relay, means con-.

trolled by the operation of said relay for operati said automaticswitch, means controll by the operation of said switch for breakingthecircuit of said relay, lines divided into roups extending from saidautomatic switc said switch having motion in one plane to select groupsand motion in a plane at right angles thereto to find a line in aselected group, a signal associated with one of the branches, and meansunder the control of the automatic switch in the other branch forrendering said signal inoperative.

overthe trunk.

22. In a. telephone system, a trunkline having two branches having acommon terminal, means for extending a talkincr connection from saidterminal over either of said branches, an automatic switch associatedwith one of said branches, said switch having motion in one plane toselect groups and motion in a plane at right ngles thereto to find aline in a selected group, a signal associated with one of the branches,and means under the control otfi said automatic switch in the otherbranch for rendering said signal inoperative over the trunk,

23. In a telephone system, a trunk. line having two branches having acommon terminal, means for extending a talking connection from saidterminal over either of said branches automatic switches as'ociated withone of sald branches a condenser in said trunk,

relay cohnected with said trunk on one side of said condenser, means for'transmittin' impulses back over the second branch of sai trunk tooperate said relay, means controlled by the operation of said relay forcontrolling the operation of said automatic switches, dines divided intogroups extending from said automatic switches, said switches havingmotion in one plane to select, groups and motion in a plane at rightangles thereto to find a line in a selected group, a signal associatedwith one of the branches, and means under the control of an automaticswitch in the other branch'for rendering said signal inoperative overthe trunk;

24. In a telephonesystem, a subscribers line, a plurality of'trunklines, a trunk-selecting switch adapted to make connection with an idleone of said trunks, each of said trunks having two branches, a springjack at the end of one of said branches, an automatic switch in whichthe other branchterminates, means associated with said spring jack fortransmitting'impulses back over one branch to operate the automaticswitch associated with the other branch of said trunk whereby a talkingcircuit is set up over the said common terminal through the medium ofthe manual switchboard, lines divided into groups" extendin from saidautomatic-switch, said switch aving motionin one plane to select groupsand motion in a plane at right angles thereto to "find a line in aselected group, a signal assoat the end of one of said branches, anautomatic switch in which the other branch terminates, a signalassociated with .each branch terminating in a jack, meansfor displayingthe corresponding signal when said trunk selecting switch makesconnection with one of said trunks, means associated with said selectedjack for transmitting im-' pulses back over one-branch of the selectedtrunk to operate the automatic switch associated with the other branchofsaid trunk, lines divided into groups extending from said automaticswitch, said switch having motion in one plane to select groups andmotion in a plane at right angles thereto to find a group, and in underthe control of said automatic switch in the other branch for renderingsaid signal inoperative over the trunk.

26. Ina telephone system, a subscrirs -matic switch in which'the otherbranch terminates, a signal, associated with ach branch terminatingin ajack, means for displaying the ccrresponding si al when saidtrunk-selecting switch ma es connection with one of said trunks, acordcircuit with a plug adapted to be connected with said selected jack,means controlled by the insertion of said plug in said jack forrendering said signal inoperative, an impulse transmitter associatedwith said cord circuit for transmitting impulses back over one branchof'said selected trunk to o crate the automatic switch associated witthe other branch of said trunk, lines divided into groups extending fromsaid automatic switch, said switch having motion in one 1 plane toselect groups and motion in a plane at right angles thereto to find aline in a selected group, and means under the control of said automaticswitch in the other branch for rendering said signal inoperative overthe trunk.

27. In a telephone system, a trunk line having two branches having acommon terminal, means for extending a talking con nection between twosubscribers via said terminal over either of said branches, auto maticprogressively movable switches associated with. one of said branches,means for transmitting impulses back over the other".

branch to operate said automatic switches, a signal associated with oneof the branches, and'means under the control of an automatic switch inthe other branch for rendering said signal inoperative over the trunk.

28. In a telephone system, a. local exchange and a distant exchange, atrunk line having two branches, having a common termeans under thecontrol of an automatic switch in the other branch for rendering saidsignal inopprative overthe trunk.

Si ed y me. at Chicago, Cook county, Illinois, this 28th day of June,1913.

I BERNARD D. LIS.

itnesses:

A. Anon, Gr. Wane a 1 minal, means for extending a talking con-

